1. Field of the Invention
The present invention relates to image forming apparatus of electrophotographic type copying apparatus, and more specifically relates to an image forming apparatus having an automatic control device for image density.
2. Description of the Related Art
In recent years, organic photosensitive members have been used mainly as the electrostatic latent image bearing members in electrophotographic type copying apparatus. Certain types of organic photosensitive members have disadvantages inasmuch as the sensitivity characteristics of the photosensitive members relative to light deteriorate, or the residual electric potential on the surface of the photosensitive members may rise as the number of times it is used increases, so as to cause an elevation in the electric potential in the background area of the image. When the electric potential becomes elevated in the background region of the image, so-called toner fogging frequently occurs which results in a decrease in contrast between the image area and the image background area.